Exploring the location patterns and clinical characteristics of isolated simple renal cysts: insights from a multicenter retrospective study.

OBJECTIVE

Surgical decisions for simple renal cysts (SRCs) depend on symptoms and compression of the renal collecting system. This study investigated the relationship between cyst location and patient clinical characteristics, offering insights into personalized management and surgical intervention.

METHODS

This study investigated hospitalized isolated SRCs patients, excluding those with renal cancer or unknown cyst sizes. Isolated SRCs were defined as a single large cyst in either kidney, accompanied by less than three additional cysts < 1 cm. Patients with two or more cysts ≥ 1 cm were excluded. Complete clinical data, including cyst location and compression effects, were required for inclusion. Ethical approval was obtained.

RESULTS

This study included 1,093 cases of isolated SRCs: extracalyceal cysts (780 patients), parapelvic cysts (158 patients), cysts above renal pelvis (78 patients), and cysts below renal pelvis (77 patients). Patients with parapelvic cysts had a greater incidence of symptoms (77.85% vs. 57.56%, 61.54%, 53.25%). Parapelvic cysts (72.15%) and cysts below the renal pelvis (88.31%) had a higher risk of collecting system compression risk than extracalyceal cysts (47.69%) and cysts above the renal pelvis (60.26%). The combined risk of hydronephrosis was higher in parapelvic cysts (46.03%) and cysts below the renal pelvis (44.44%) than in extracalyceal cysts (8.96%) and cysts above the renal pelvis (0.00%). Cox regression analysis revealed that cyst size at diagnosis (p < 0.001) and the presence of parapelvic cysts (p < 0.001) independently contributed to symptomatic risk. Cyst size at diagnosis (p < 0.001), parapelvic cysts (p < 0.001), and cysts below the renal pelvis (p < 0.001) were independent predictors of hydronephrosis in patients with SRCs.

CONCLUSION

SRCs in different kidney locations have unique features, necessitating tailored management. Cysts size at diagnosis and the presence of parapelvic cysts independently contribute to the symptoms of patients with SRCs. Parapelvic cysts and cysts below the renal pelvis are independent risk factors for hydronephrosis and should be actively managed.